U.S. patent application number 10/467464 was filed with the patent office on 2004-11-04 for caliper for a disc brake.
Invention is credited to Piccoli, Mauro, Veneziano, Aristide.
Application Number | 20040216967 10/467464 |
Document ID | / |
Family ID | 30776591 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040216967 |
Kind Code |
A1 |
Veneziano, Aristide ; et
al. |
November 4, 2004 |
Caliper for a disc brake
Abstract
A disc-brake caliper comprises a caliper body suitable for being
associated with a disc and has at least one seat suitable for
housing a pad which cooperates with thrust means in order to
generate a braking force on the disc. The caliper also comprises a
brake-fluid distribution circuit for supplying the brake fluid to
the thrust means, and at least one reinforcing element disposed
between a first portion and a second portion of the caliper body in
the region of the seat for the pad. The connection element
comprises at least a portion of the brake-fluid distribution
circuit.
Inventors: |
Veneziano, Aristide;
(Lallio, IT) ; Piccoli, Mauro; (Bergamo,
IT) |
Correspondence
Address: |
HOGAN & HARTSON LLP
IP GROUP, COLUMBIA SQUARE
555 THIRTEENTH STREET, N.W.
WASHINGTON
DC
20004
US
|
Family ID: |
30776591 |
Appl. No.: |
10/467464 |
Filed: |
August 7, 2003 |
PCT Filed: |
July 30, 2002 |
PCT NO: |
PCT/IT02/00507 |
Current U.S.
Class: |
188/72.5 |
Current CPC
Class: |
F16D 55/228 20130101;
F16D 2055/0091 20130101; F16D 2055/002 20130101 |
Class at
Publication: |
188/072.5 |
International
Class: |
F16D 055/228 |
Claims
What is claimed is:
1. A disc-brake caliper comprising: a caliper body suitable for
being associated with a disc with a first annular braking surface
and a second annular braking surface remote from the first, the
caliper body having, in a configuration in which it is associated
with the disc, a first portion facing towards the first braking
surface of the disc and a second portion facing towards the second
braking surface of the disc, at least one seat formed in the
caliper body for housing a pad which cooperates with thrust means
which are acted on, during a braking operation, by a brake fluid in
order to press on the pad so as to cause it to interact with the
braking surfaces of the disc in order to generate a braking force,
a brake-fluid distribution circuit suitable for supplying the brake
fluid to the thrust means, at least one connection element between
the first portion and the second portion of the caliper body, which
connection element is arranged, in the configuration in which the
caliper body is associated with the disc, straddling the disc in
the region of the at least one seat for the pad, the connection
element comprising at least a portion of the brake-fluid
distribution circuit.
2. A caliper according to claim 1 in which the connection element
joins the portions of the caliper body together and is arranged in
a "bridge" configuration between them.
3. A caliper according to claim 1 in which the connection element
forms a reinforcing cross-member for the caliper body.
4. A caliper according to claim 1 in which the connection element
operates as a stay, limiting the deformation of the portions of the
caliper body, during a braking operation.
5. A caliper according to claim 1 in which the connection element
is formed integrally with the caliper body.
6. A caliper according to claim 1 in which the connection element
is an applied element.
7. A caliper according to claim 1 in which each portion of the
caliper body has at least one pressure chamber for slidably housing
thrust means for acting on the pad.
8. A caliper according to claim 7 in which the thrust means are
hydraulic pistons.
9. A caliper according to claim 1 in which each portion of the
caliper body has a first pressure chamber and a second pressure
chamber.
10. A caliper according to claim 9 in which the nominal diameter of
the first pressure chamber is less than the nominal diameter of the
second pressure chamber, the first chamber being disposed upstream
of the second chamber, with reference to the direction of rotation
of the disc suitable for being associated with the caliper.
11. A caliper according to claim 1 in which the distribution
circuit has longitudinal ducts each formed entirely in a respective
portion of the caliper body.
12. A caliper according to claim 11 in which the longitudinal ducts
comprise, in each portion of the caliper body, a longitudinal hole
communicating simultaneously with both pressure chambers.
13. A caliper according to claim 11 in which the longitudinal ducts
comprise, in each portion of the caliper body, a first longitudinal
hole and a second longitudinal hole.
14. A caliper according to claim 13 in which the longitudinal holes
extend along converging hole axes.
15. A caliper according to claim 13 or claim 14 in which the
longitudinal holes meet in a joining portion so as to be in
communication with one another.
16. A caliper according to claim 1 in which each portion of the
caliper body has a first pressure chamber and a second pressure
chamber, the distribution circuit having longitudinal ducts each
formed entirely in one of the portions of the caliper body and
comprising a first longitudinal hole and a second longitudinal hole
which are in communication with the first pressure chamber and with
the second pressure chamber, respectively.
17. A caliper according to claim 1, provided with at least one
supply aperture which is in communication with the distribution
circuit and is provided for the connection of the caliper body to
brake-fluid supply means.
18. A caliper body according to claim 11 in which the distribution
circuit comprises transverse ducts which are in communication with
the longitudinal ducts.
19. A caliper according to claim 18 in which the transverse ducts
extend from a lower portion of the caliper body facing the disc to
an upper portion thereof, and converge towards a plane of symmetry
of the caliper body.
20. A caliper according to claim 19 in which the transverse ducts
comprise a first transverse hole formed in the first portion of the
caliper body and a second transverse hole formed in the second
portion thereof.
21. A caliper according to claim 1 in which the portion of the
distribution circuit which is included in the connection element
forms axial ducts.
22. A caliper according to claim 21 in which the axial ducts
comprise at least one axial hole.
23. A caliper according to claim 22 in which the axial hole enables
longitudinal ducts formed in the first portion of the caliper body
to be put into communication with longitudinal ducts formed in the
second portion thereof.
24. A caliper according to claim 1, comprising longitudinal ducts
which are formed in each portion of the caliper body and the
openings of which are closed by removable plugs in an operative
condition of the caliper.
25. A caliper according to claim 24 in which the plugs form bleed
valves.
26. A caliper according to claim 1 further comprising means for
connecting the caliper body to a fixed portion of the vehicle.
27. A caliper according to claim 26 in which the connection means
comprise connection holes.
28. A caliper according to claim 27 in which there are two
connection holes, both formed in one of the portions of the caliper
body.
29. A caliper according to claim 1 in which the connection element
is provided with a duct formed by an axial channel facing the
disc.
30. A caliper according to claim 29 in which the duct is covered by
the wall of a cover.
31. A caliper according to claim 30 in which the wall of the cover
is made of sheet steel.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a disk-brake caliper
provided with ducts for supplying the brake fluid to the thrust
means for the pads, such as hydraulic pistons and the like.
[0002] The caliper according to the invention is intended
particularly but not exclusively for automotive use, generally in
high-performance motor cars, for example, racing cars.
BACKGROUND OF THE INVENTION
[0003] A disc brake comprises a disc-brake caliper and a disc. The
disc has an axis of rotation and annular braking surfaces lying in
opposed planes perpendicular to the axis of rotation. In the
assembled configuration, the caliper is arranged astride the disc
and has a first portion provided with pressure chambers facing the
first braking surface thereof and a second portion provided with
pressure chambers facing the second braking surface.
[0004] The caliper body has ducts which form a brake-fluid
distribution circuit by means of which the fluid is supplied to the
hydraulic pistons.
[0005] It is known to form the brake-fluid distribution circuit as
a series of holes inside the caliper body, which form a circuit
closed in a "loop" which is supplied at a single point of the
caliper body and enables the brake fluid to be distributed both to
the pressure chambers of the first portion of the caliper body and
to the pressure chambers of the second portion thereof.
[0006] However, the implementation of a solution as described is
complex because of the large number of holes to be formed in the
caliper body and, consequently, because of the need to provide
numerous plugs to close the openings of the holes from the
exterior.
[0007] It is also known to produce a distribution circuit in which
purely longitudinal holes are provided, included entirely in the
first portion and in the second portion of the caliper body,
respectively, and connected outside the caliper body by a pipe
which, when the caliper has been mounted in the vehicle, will be
arranged straddling the disc in the region of a bridge portion
which connects the first and second portions of the caliper body at
their ends.
[0008] However, constructions such as that just described have
exhibited problems connected with vibration of the pipe, which lead
to rupture of the pipe, mainly in the region of the attachment to
the holes in the caliper body.
[0009] There is therefore a need to provide a disc-brake caliper
which has a brake-fluid distribution circuit which is reliable in
use and at the same time can be produced easily and
economically.
OBJECTS OF THE INVENTION
[0010] The problem underlying the present invention is that of
devising a disc-brake caliper provided with a brake-fluid
distribution circuit which has structural and functional
characteristics such as to satisfy the above-mentioned needs and at
the same time to overcome the disadvantages mentioned with
reference to the prior art.
SUMMARY OF THE INVENTION
[0011] This problem is solved by a caliper according to claim
1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Further characteristics and the advantages of the caliper
according to the present invention will become clear from the
following description of a preferred and non-limiting embodiment
thereof, in which:
[0013] FIG. 1 is an axonometric view of a disc-brake caliper
according to the present invention,
[0014] FIG. 2 is a side view of the caliper of FIG. 1, viewed along
the line A,
[0015] FIG. 3 shows the caliper of FIG. 1 in a section taken in
section planes indicated by the line BB in FIG. 2,
[0016] FIG. 4 shows the caliper of FIG. 2 in a section taken in a
section plane indicated by the line CC in FIG. 2,
[0017] FIG. 5 is a plan view of the caliper of FIG. 1, viewed along
the line D, and
[0018] FIG. 6 shows schematically a configuration of mounting of
the caliper of FIG. 1 on the left-hand front and left-hand rear
wheels of a motor vehicle.
DETAILED DESCRIPTION
[0019] With reference to the drawings, a disc-brake caliper is
generally indicated 1.
[0020] The caliper 1 comprises a caliper body 2 which is intended
to cooperate, in an assembled configuration of the disc brake, with
a disc.
[0021] The disc has a predefined axis of rotation about which the
disc rotates, firmly fixed to the wheel hub of a vehicle, during
the normal operation of the brake.
[0022] In the following description, where reference is made to an
axial direction for the caliper body, it is intended to refer to
the direction of the axis of rotation of the disc which can be
associated with the caliper body and, similarly, with reference to
the disc itself, reference will be made to a circumferential or
longitudinal direction, meaning a direction substantially
tangential to a circumference of the disc.
[0023] The disc also has, disposed in planes perpendicular to its
axis of rotation, a first annular braking surface and a second
annular braking surface, opposite to the first.
[0024] In the configuration in which it is associated with the
disc, the caliper body 2 is arranged astride the disc, with a first
portion 2a of the caliper facing towards the first braking surface
of the disc and a second portion 2b thereof facing towards the
second braking surface of the disc.
[0025] Moreover, when the caliper body 2 is arranged astride the
disc, a portion of the caliper body 2 faces towards the axis of
rotation of the disc and an opposed portion is arranged astride the
disc. The portion of the caliper body which faces towards the axis
of rotation of the disc will be referred to below by the term
"lower portion of the caliper body" and the portion opposite to the
lower portion by the term "upper portion of the caliper body".
[0026] Furthermore, a plane of symmetry Y-Y defined for the caliper
body is arranged perpendicular to the axis of rotation of the disc
and extends centrally through the caliper body.
[0027] The first and second portions of the caliper body 2 are
connected to one another by a first end element 4 and by a second
end element 6 which are disposed at the circumferential ends of the
portions of the caliper body and constitute elements joining the
said portions.
[0028] In other words, the first and second portions of the caliper
body, joined together by the end elements, form a closed annular
block which, when associated with the disc, has the end elements
arranged astride the disc.
[0029] According to a variant, the caliper body is unitary, that
is, it is formed from a single solid block, for example, it is
produced from a rolled section or from a semi-finished casting,
preferably of aluminium alloy, suitably machined by means of
machining operations such as milling, drilling, and the like.
[0030] Each portion of the caliper body has, on the outside of its
portion which faces the disc, a first inclined surface 8a and a
second inclined surface 8b which are preferably flat and lie in
converging planes, and each of which is disposed in the region of a
circumferential end of the said portion of the caliper body.
[0031] In a preferred embodiment, the inclined surfaces converge
towards the lower portion of the caliper body. In a further
embodiment, the inclined surfaces are parallel to one another.
[0032] Preferably, the inclined surfaces delimit a protruding wall
8 circumferentially.
[0033] The caliper body 2, configured as a closed annular block as
described above, has a window 10 disposed in a central position
relative thereto and delimited by the portions 2a, 2b of the
caliper body and by the end elements 4, 6.
[0034] The window 10 forms, in particular, an opening towards the
space inside the caliper body, delimited by the portions 2a, 2b of
the caliper body and by the end elements.
[0035] In the region of the window 10 of the caliper body 2, the
caliper body has at least one connection element 12 between the
first portion 2a and the second portion 2b of the caliper body. In
the configuration in which the caliper body 2 is associated with
the disc, the at least one connection element 12 is arranged
straddling the disc.
[0036] In other words, the connection element 12 joins the portions
of the caliper body together, and is arranged in a "bridge"
configuration, forming a connection between them.
[0037] In a preferred embodiment of the caliper body, the
connection element 12, which is preferably single, extends
substantially axially and forms an element for reinforcing the
caliper body 2.
[0038] Whereas the portions 2a, 2b of the caliper body and the end
elements 4, 6 form a closed annular structure, the connection
element joins central portions of the portions 2a, 2b of the
caliper body.
[0039] In other words, the connection element 12 forms a
cross-member reinforcing the caliper body, disposed in the region
of the window 10 of the caliper body.
[0040] During a braking operation, the connection element 12
advantageously operates as a stay, limiting the deformation of the
portions of the caliper body due to the clamping force generated by
the thrust of the pistons. In particular, bending is limited by
virtue of the arrangement of the connection element 12 in the
region of the upper window 10 of the caliper body and by virtue of
its strength characteristics.
[0041] In a preferred embodiment, the connection element 12 is
formed integrally with the caliper body. Further variants of the
caliper body according to the invention provide for an applied
connection element, or for a plurality of connection elements
arranged, for example, between the portions of the caliper body in
non-axial directions.
[0042] In the region of the window 10, the caliper body 2 has,
formed in each portion thereof, at least one seat 14 for housing a
pad 16. The connection element 12, which is preferably disposed in
the region of the upper window 10 of the caliper body 2, is
arranged in the region of the seats for housing the pads.
[0043] The seat 14 is in the form of a square recess formed in each
portion of the caliper body in a manner such as to define a pocket
suitable for housing the pad 16.
[0044] In particular, the seat is defined between a first side wall
18 and a second side wall 20, opposite the first, which side walls
define the circumferential extent of the seat, as well as by a base
wall 22.
[0045] The pad 16, comprising a plate 24 and friction material 26
supported by the plate, is arranged, when it is housed in its seat
14, in a manner such that the plate 24 faces the base wall 22 of
the seat 14 and the friction material 26 faces towards one of the
braking surfaces of the disc, in the configuration in which the
caliper is associated with the disc.
[0046] In the region of the base wall 22 of the seat 14, each
portion of the caliper body has at least one pressure chamber for
slidably housing thrust means for pressing on the pad so as to
cause it to interact, in the course of a braking operation, with
the braking surface of the disc which the friction material of the
pad faces. Preferably, the thrust means are formed by hydraulic
pistons.
[0047] In a preferred embodiment, the pressure chamber is
substantially cylindrical and is arranged axially. The pressure
chamber is defined dimensionally by its nominal diameter.
[0048] In a preferred embodiment of the caliper body, each portion
thereof has a plurality of pressure chambers, preferably a first
pressure chamber 28 and a second pressure chamber 30, for housing
respective first and second thrust means.
[0049] Preferably, the nominal diameter of each pressure chamber is
different from one chamber to another. In particular, the nominal
diameter of the first pressure chamber 28 is less than the nominal
diameter of the second pressure chamber 30.
[0050] The pressure chambers are arranged in the region of the seat
14 of the pad 16 in a manner such that, with reference to the
direction of rotation of the disc during the normal and predominant
use of the brake, that is, when the vehicle is moving forwards, the
pressure chamber with the smaller diameter is disposed upstream of
the pressure chamber with the larger diameter.
[0051] The thrust means housed in the respective pressure chambers
are acted on, during a braking operation, by the pressurized brake
fluid which operates the thrust means so that the pad is pressed
against the respective braking surface of the disc in order to
generate the braking force. The brake fluid is supplied to the
thrust means by a distribution circuit.
[0052] In a preferred embodiment, the distribution circuit has
longitudinal ducts 32 which preferably comprise a first
longitudinal hole 32a and a second longitudinal hole 32b.
[0053] The longitudinal ducts are formed entirely in the respective
portions 2a, 2b of the caliper body.
[0054] In one embodiment, each of the longitudinal holes extends
along a hole axis H-H substantially perpendicular to the inclined
surfaces 8a and 8b which delimit the protruding wall 8
circumferentially.
[0055] The inclination of the axes of the longitudinal holes is
predetermined in a manner such that the holes converge, preferably
towards the upper portion of the caliper body.
[0056] In a further embodiment, the longitudinal ducts 32 comprise
a single longitudinal hole formed in each portion of the caliper
body so as to extend completely through the portion of the caliper
body, communicating with both of the pressure chambers
simultaneously.
[0057] Preferably, the first longitudinal hole 32a and the second
longitudinal hole 32b with converging axes meet in a joining
portion 34 of the circuit so as to be in communication with one
another.
[0058] Moreover, each of the holes is in communication with at
least one of the pressure chambers 28, 30 of the caliper body. In
particular, according to a preferred embodiment, the first
longitudinal hole 32a is in communication with the first pressure
chamber 28 and the second longitudinal hole 32b is in communication
with the second pressure chamber 30. The longitudinal holes
continue along their respective axes so as also to extend beyond
the pressure chamber, terminating, at one end, in the joining
portion 34 and, at the other end, in the inclined surfaces.
[0059] In other words, the longitudinal holes have a portion
disposed between the inclined surface of the caliper body and the
pressure chamber thereof, and a portion extending from the first
and disposed between the pressure chamber and the joining portion
in which it joins the other longitudinal hole.
[0060] The longitudinal holes 32a, 32b are preferably blind, that
is, each has a single opening, preferably disposed in a respective
inclined surface 8a, 8b of a portion 2a, 2b of the caliper body,
and terminates in the joining portion 34 inside the caliper
body.
[0061] At least one of the portions of the caliper body also has a
supply aperture 36 provided for the connection of the caliper body
to external supply means such as flexible or rigid pipes connected,
for example, to a disc-brake master cylinder.
[0062] The supply aperture is in communication with the
distribution circuit and, preferably, is in communication with the
joining portion 34 between the longitudinal holes 32a, 32b.
[0063] In a preferred embodiment of the caliper body, the supply
aperture is constituted by a hole formed in the protruding wall 8
of the caliper body, substantially in an axial direction.
[0064] In a further embodiment of the caliper according to the
invention, the distribution circuit comprises transverse ducts 38
in communication with the longitudinal ducts 32.
[0065] Preferably, the transverse ducts are formed by transverse
holes which extend from the lower portion of each caliper body to
its upper portion, converging towards the plane of symmetry Y-Y of
the caliper body.
[0066] In a preferred embodiment, the distribution circuit
comprises a first transverse hole 39a in the first portion 2a of
the caliper body 2 and a second transverse hole 39b in the second
portion 2b thereof.
[0067] The transverse holes extend through the joining portion 34
between the longitudinal holes 32a, 32b and terminate in the region
of the connection element 12 between the portions of the caliper
body.
[0068] Preferably, the transverse holes 39a, 39b, which are formed
entirely within the caliper body, are blind, that is, each hole has
only one opening in the upper portion of the caliper body or,
preferably, in its lower portion.
[0069] The distribution circuit further comprises at least one
portion which is disposed in the at least one connection element 12
between the portions of the caliper body.
[0070] In other words, the distribution circuit comprises axial
ducts 40 constituted by at least one axial hole 42 formed in the
connection element 12 between the portions 2a, 2b of the caliper
body 2.
[0071] In yet other words, the connection element 12 comprises a
portion of the distribution circuit which puts the longitudinal
ducts 32 and the transverse ducts 38 of the first portion 2a of the
caliper body 2 into communication with the transverse ducts 38 and
the longitudinal ducts 32 of the second portion 2b of the caliper
body 2.
[0072] The portion of the distribution circuit which is formed in
the connection element 12 disposed in the region of the window 10
of the caliper body, is arranged straddling the disc and is formed
in an element facing the window 10 of the caliper body 2.
[0073] In a preferred embodiment, the portion of the distribution
circuit which is contained in the connection element 12 is formed
by a blind hole, that is, by a hole having a single opening 44
formed in one of the portions of the caliper body and terminating
in the transverse hole formed in the opposite portion of the
caliper body.
[0074] In an operative condition of the caliper, that is, in a
condition in which the caliper is ready to be associated with the
disc, the openings of the ducts which form the brake-fluid
distribution circuit are closed, with the exception of the supply
aperture 36 disposed in one of the portions 2a, 2b. This aperture
is provided for the connection of the caliper body to external
brake-fluid supply means with which it is associated when the disc
brake is in the mounted condition on the vehicle.
[0075] In particular, in the operative condition, the openings of
the transverse ducts 38 and of the axial ducts 40 are closed by
plugs (not shown) each formed by a sphere restrained by a grub
screw.
[0076] In particular, in the operative condition of the caliper,
the openings of the longitudinal holes are closed by removable
plugs which form bleed valves.
[0077] In the embodiment described of the caliper according to the
invention, the caliper has four bleed valves.
[0078] In particular, the caliper comprises a first bleed valve 46
and a second bleed valve 48 which close the first longitudinal hole
32a and the second longitudinal hole 32b of the first portion 2a of
the caliper body 2, respectively. Moreover, the caliper comprises a
first bleed valve 50 and a second bleed valve 52 which close the
first longitudinal hole 32a and the second longitudinal hole 32b of
the second portion 2b of the caliper body 2, respectively.
[0079] Furthermore, the caliper body has, preferably in only one of
the portions 2a, 2b of the caliper body, means for the connection
of the caliper body to a fixed portion of the vehicle for which the
caliper is intended. According to a preferred embodiment, the
connection means comprise a pair of connection holes 54', 54".
[0080] In a preferred embodiment, the connection holes are disposed
in the region of the connection between the first portion 2a of the
caliper body 2 and the first end element 4, and between the first
portion 2a of the caliper body 2 and the second end element 6 of
the caliper body 2, respectively.
[0081] In a condition in which the disc brake is mounted in the
vehicle for which it is intended, the disc is fixed firmly to the
wheel hub and the caliper, which is operatively connected to
brake-fluid supply means such as a flexible pipe connected to the
supply aperture 36, is fixed firmly to a non-rotating part of the
vehicle, for example, to a part of the suspension.
[0082] By way of example, reference is made to the mounting of the
caliper in the region of the left-hand front wheel of a vehicle
(FIG. 6), preferably in a position at the rear of the wheel, with
reference to the direction of forward movement Ma of the
vehicle.
[0083] The caliper is mounted in a manner such that the connection
holes 54' and 54" of the caliper body are disposed towards the
inside of the vehicle, for connection to the suspension units. The
brake-fluid supply aperture 36 is also arranged facing towards the
inside of the vehicle, to facilitate connection to the fluid-supply
means.
[0084] The disc associated with the caliper passes through the
caliper body in a direction of forward movement E so that, with
reference to the direction of forward movement, the first pressure
chamber 28 having a nominal diameter smaller than the nominal
diameter of the second pressure chamber 30 is upstream of the
second pressure chamber 30.
[0085] In a parked condition of the vehicle, the vehicle is
disposed on a supporting surface P so that, in the mounted
configuration of the disc brake, the second end element 6 of the
caliper body faces upwards.
[0086] Advantageously, each of the portions of the caliper body has
a bleed valve which is disposed, relative to the surface P
supporting the vehicle, at a level higher than the level at which
any other point of the brake-fluid distribution circuit is
disposed.
[0087] In the example of mounting described, the second bleed valve
48 of the first portion 2a of the caliper body and the second bleed
valve 52 of the second portion 2b of the caliper body 2 are
suitable for being used as bleed valves for performing conventional
bleeding operations.
[0088] The embodiment described of the caliper according to the
invention can advantageously be used for mounting in the region of
the left-hand rear wheel of the vehicle, in which the caliper is
preferably disposed at the front of the wheel, with reference to
the direction of forward movement Ma.
[0089] In this case, the caliper is mounted in a manner such that
the connection holes 54' and 54" and the brake-fluid supply
aperture 36 of the caliper body are disposed towards the inside of
the vehicle.
[0090] The disc associated with the caliper passes through the
caliper body in the direction of forward movement E so that, with
reference to the direction of forward movement, the first pressure
chamber 28 which has a nominal diameter smaller than the nominal
diameter of the second pressure chamber 30 is upstream of the
second pressure chamber 30.
[0091] In the parked condition of the vehicle, the vehicle is
disposed on the supporting surface P so that, in the
above-mentioned mounted configuration, the first end element 4 of
the caliper body faces upwards relative to the remaining portion of
the caliper body.
[0092] Advantageously, in the configuration in which it is mounted
on the left-hand rear wheel, the caliper also has bleed valves
which are disposed, relative to the surface P supporting the
vehicle, at a level higher than the level at which any other point
of the brake-fluid distribution circuit is disposed.
[0093] In the embodiment described, the first bleed valve 46 of the
first portion 2a of the caliper body and the first bleed valve 50
of the second portion 2b of the caliper body 2 are suitable for
being used as bleed valves for performing conventional bleeding
operations.
[0094] In a further embodiment of the caliper according to the
invention, the connection holes 54' and 54" and the supply aperture
36 are disposed in the second portion 2b of the caliper body 2.
[0095] This embodiment is advantageously usable for the mounting of
the caliper on the right-hand front wheel and on the right-hand
rear wheel.
[0096] For mounting on the right-hand front wheel, the second valve
48 of the first portion 2a of the caliper body and the second valve
52 of the second portion 2b of the caliper body are usable as bleed
valves.
[0097] For mounting on the right-hand rear wheel, the first valve
46 of the first portion 2a of the caliper body and the first valve
50 of the second portion 2b of the caliper body are usable as bleed
valves.
[0098] The caliper according to the invention thus advantageously
provides at least one valve which is disposed at a level higher
than the level of any point of the distribution circuit, and which
is suitable for being used as a bleed valve since it is not engaged
by further devices such as external pipes of the distribution
circuit or the like.
[0099] According to a further advantageous aspect, in order to
provide the calipers necessary for mounting on the vehicle in the
front and rear positions as well as the left-hand and right-hand
positions, it is necessary to produce only two ranges of calipers,
which preferably differ solely in the arrangement of the
brake-fluid supply apertures and of the holes for connection to the
vehicle.
[0100] The number of ranges of calipers to be produced is thus
advantageously reduced, with clear advantages for the
simplification of production, storage and management.
[0101] In a further variant, the caliper has a pair of connection
holes in each portion of the caliper body, a supply aperture in the
first portion thereof, and a further supply aperture in the second
portion.
[0102] In this variant, the caliper is advantageously usable for
mounting on all four wheels, by suitably closing the supply
aperture which is not used and preferably closing the connection
holes which are not used.
[0103] Unusually, the caliper according to the invention has a
brake-fluid distribution circuit which is reliable in use and at
the same time can be produced easily and economically.
[0104] Advantageously, the caliper according to the invention makes
use of the connection element, which is provided for improving the
bending strength of the caliper body, for connecting the holes that
are provided in the two portions of the caliper body.
[0105] Advantageously, the holes formed in the portions of the
caliper body converge towards a joining portion from which the
axial hole included in the connection element between the portions
extends, and have their respective openings closed by plugs which
are suitable for being used as bleed valves in the various
configurations of mounting of the caliper on the vehicle.
[0106] According to a further advantageous aspect, the inclination
of the longitudinal holes enables them to overcome the considerable
circumferential curvature of calipers intended for high-performance
vehicles, establishing communication between the supply aperture,
which is arranged centrally relative to the portion of the caliper
body, and the openings of the longitudinal holes which are disposed
at the circumferential ends of the portion.
[0107] Naturally, in order to satisfy contingent and specific
requirements, a person skilled in the art will be able to apply
many modifications and variations to the above-described disk-brake
caliper.
[0108] According to a further variant of the caliper according to
the invention, the connection element between the first portion and
the second portion of the caliper body has a further duct formed in
the connection element and facing the disc. The duct is preferably
formed by an axial channel formed in the connection element and
covered by the wall of a cover, preferably of sheet steel. The duct
is advantageously provided for a flow of cooling air.
[0109] With regard to the provision of the above-mentioned cooling
duct, reference is made to the Applicant's document EP1016804, the
teaching of which is incorporated herein by reference.
[0110] According to an advantageous aspect, the above-mentioned
variant provided with the cooling duct, which is arranged between
the portion of the distribution circuit that is disposed in the
connection element and the disc, protects the brake fluid contained
in this portion of the distribution circuit from excessive heating
due mainly to its proximity to the hot disc.
[0111] Naturally, these variants are also intended to be included
within the scope of protection of the invention as defined by the
appended claims.
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